This is a loose sequel to Farthing. It takes place in the same world, but most of the characters are different. Events from Farthing directly inform this story, but it's a complete story in itself and would make sense on its own. Now that I think about it, in fact, I think Ha'penny would probably stand better on its own, even if it was a tiny bit less clear, because while it's continuing the same general message, it is more subtle about it, and a slap in the face is less effective right after a hard kick in the gut. It tells an interesting story, and I at least was really wondering how it would turn out until the big event actually happened, but it doesn't grab me by the throat and say "You must make sure everyone reads this!" the way Farthing did. It's a decent read and it reinforces the message, but it's not a world I want to live in. 7 out of 10.
**** PLOT SUMMARY -- SPOILERS ****
I have to confess that I've let this sit long enough that I'm having trouble remembering the details of the plot, so this is going to be a less detailed summary than usual.
Viola Lark is an actress and doesn't care about politics. She doesn't like Hitler but certainly doesn't have any notions of being involved in fighting him. She's very happy to have landed the lead in Hamlet (it seems cross-casting is the In Thing in London theater), and excited that Hitler and the Prime Minister are attending the opening. Then Lauria Gilmore, the actress cast as Gertrude, is blown up by a bomb. And it turns out that Lauria was actually making the bomb, not just a victim, and Viola gets pulled into the conspiracy by her sister. She is quite unwilling at first, but she is given the choice of agreeing or being killed, and goes along with it. And by the end, she's actually believing in the cause, and in love with the terrorist who was her minder.
Inspector Carmichael is hot on the trail of the conspiracy, but he's attending the opening by pure coincidence (Hitler's security requires filling the other boxes with plainclothes police) when he puts the pieces together. He gets the message off and the royal box is being evacuated when the bomb goes off. Hitler and the PM survive, but Himmler (who is married to Viola's sister) is killed. It is only after he's done his job that Carmichael realizes that, had he just sat there for a few minutes, the plot would have worked. The new government is implementing its own Gestapo, and they've tapped Carmichael to lead it just when he meant to resign. He's a very conflicted hero. I think I've heard that there's a third book coming for him to redeem himself.